Energy Storage in Plants: Should Biofuels Be Made from Seeds or Leaves and Stems?

The investigation involves students determining where plants store potential energy (a.k.a., chemical energy). In the investigation, students will grow rapid cycling Brassica rapa plants and observe that the dry weight (mass) increases because of photosynthesis. They will measure the amount of energy stored in seeds and vegetative tissues by using a simple calorimeter. The information collected by the students is evaluated as it relates to potential sources of biofuels.

The students make calorimetry measurements and dry weight measurements to show that plants gain mass and energy through the process of photosynthesis. Elements of directed inquiry are used because the students are not given the expected results of their experiments. The student are asked to relate their results to the summary equation of photosynthesis.